What does Bruno ask Gretel about and what answer does she give him?

Bruno has begun to wonder more and more about why he and Shmuel are living on opposite sides of the fence, so he decides to ask Gretel about it. She has thrown away all of her dolls and replaced them with maps of Europe. When he asks her about the fence, she first corrects him on his pronunciation of "Out-With." Then she explains that the people on the other side of the fence are Jews and that the fence is there to keep them from getting out and mixing with anyone else. When Bruno asks her what he and their family are, if not Jews, she says simply that they are "the opposite" (183).